Focusing mechanism of diffusion of dynamic crowdions

摘要

A new mechanism of diffusion of dynamic crowdions is considered. On the basis of a model of a one-dimensional dynamic crowdion, a molecular dynamics (MD) calculation has been made to clarify the peculiarities of crowdion motion. It is shown that the origin of thermally activated correlated jumps observed in MD calculations is analogous in many of its features to focused collisions. A random-walk model with jumps of various lengths is assumed as a theoretical description of crowdion motion. A kinetic equation formalism related to this model is developed to explain the MD results. Deviation from the Arrhenius law observed earlier can also be explained as a result of extended jump length. Strong deviation of the mean square displacement from a linear time dependence was found for short times. [References: 11]